Method for recycling glass

ABSTRACT

A process and apparatus are provided for breaking the glass components of articles comprised of glass and nonglass components and liberating the glass components from the nonglass components by subjecting the articles to controlled vibrations sufficient to break the glass without breaking the nonglass components. The apparatus is a vibratory device having a screen deck and a plate deck. The screen deck has holes through which the broken glass falls to the plate deck. The nonglass components remain on the screen deck. Thereafter, the nonglass components are removed by one or more of a variety of means. The glass may be further processed by cleaning, rinsing and further crushing to size the glass pieces. Glass of different types may optionally be separated by taking advantage of the differences in specific gravities between glass types.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to processes for recycling glass, and moreparticularly, to a process for separating the glass components fromnonglass components of glass containing articles.

2. Description of the Invention Background

In 1990, an estimated 18-20 million television sets were sold in theUnited States. A single television manufacturing facility may producefrom 7,000 to about 15,000 television picture tubes per day. Of these,between about five to seven percent are rejected due to some defectrendering them unsuitable for sale. Thus, at a single manufacturingfacility, hundreds of TV tubes are discarded each day amounting toseveral hundred tons of TV tube waste each month. The traditional meansof disposing of the waste has been to put it in land fills.

A television tube typically contains glass components and nonglasscomponents. The glass components include a front panel, which is up totwo inches thick in places, and a conical funnel section. The nonglasscomponents include paper, plastics, ceramics and metals in the form ofthe electronic gun, clips, masks, straps and a lead frit used to jointhe panel glass to the funnel glass. A graphite acrylic coatingtypically is applied to the external surfaces of the panel glass and thefunnel glass. The internal surface of the panel glass is also coatedwith, for example, aluminum, phosphor and graphite. The internal surfaceof the funnel glass may be coated with graphite, iron oxide and sodiumsilicate.

Because the glass TV tubes exhibit toxic waste characteristics due toleaching of lead from the frit and funnel, they are disposed of as ahazardous waste. Simply burying the TV tubes is no longer permissible.Transport of the waste to approved toxic land fills is costly.

Heretofore, there has been no effective means of recycling the waste TVtubes or other articles made of glass and nonglass components. Thestructural mixture of glass and nonglass components and the inorganicand organic coatings on the glass in TV tubes makes them unacceptablefor recycling by conventional glass or metal recycling methods. Inaddition, the ceramic components in the TV tubes would poison the glassfor most further uses if the glass and ceramics are mixed. Avoiding sucha mixture was heretofore very difficult. Crushing the discarded TV tubesby conventional means only inextricably mixes the glass and nonglasscomponents. The safe disposal and/or recycling of TV tubes and similarmixed glass and nonglass articles has become a problem.

There is a need for a process for separating the glass and nonglasscomponents of a TV tube or similarly structured article. There is afurther need for a process for sizing and cleaning the separated glassfor recycling. Finally, there is a need for a process for separatingdifferent types of glass, such as the panel glass from the funnel glass,in an economic and easy to use process.

SUMMARY OF THE INVENTION

The process of the present invention involves generally coarse breakingof the glass to liberate it from the nonglass components followed byseparation of the glass and nonglass components. It may be advantageousto size the glass and clean it for storage and further use. A feed stockof waste materials, including articles and portions thereof made ofglass and nonglass components, articles and portions thereof made ofglass, glass shards, and combinations thereof, is subjected tovibrations in a vibratory apparatus at a frequency, impact force, andfor a period of time effective for breaking substantially all of theglass components into pieces of glass of a first size range and forliberating from the nonglass components generally all of the glassconnected to such nonglass components. Thereafter, the nonglasscomponents present in the feed stock are separated from the pieces ofglass, either in the vibratory apparatus or outside of such apparatus.

The process also preferably includes the steps of removing any coatingfrom the glass, rinsing the glass and sizing the glass by subjecting itto one or more vibrating crushing steps to break the pieces of glassinto a second or third range of sizes. The preferred method of removingcoatings is to bathe the glass in acid in a vibratory circular conveyor.The composition of the bath depends on the kind of coatings to beremoved. The preferred method of rinsing is by means of a countercurrentwashing operation. Alternatively, the glass pieces may simply be sprayedwith water or some other rinsing agent until the residue from the bathis removed.

An optional step in the process permits separation of two types of glasshaving different specific gravities.

Prior to using the glass in a further glass making process, samples ofthe glass may be removed for analysis of the glass composition.

The vibratory apparatus of the present invention used for the initialcoarse breaking of the glass and liberatic, n of the glass from nonglasscomponents includes an inlet, a first deck and a second deck. The firstdeck has an elevated surface, a step, a lower surface and a firstoutlet. The second deck has a second outlet. Means are provided forvibrating the first deck at a predetermined frequency. Openings in theelevated and lower surfaces of the first deck are sized to permit itemsof a desired size, such as broken glass, to fall through the openings tothe second deck and exit through the second outlet. Items larger thanthe desired size, such as the nonglass components, remain on the firstdeck and exit through the first outlet.

DESCRIPTION OF THE DRAWINGS

The present invention can be better understood by reference to thedrawings which are intended to be illustrative only of the preferredembodiments of the process and apparatus of the present invention.

FIG. 1 is a schematic view of the steps of one embodiment of the processof the present invention.

FIG. 2 is a schematic view of the steps of an alternative embodiment ofthe process of the present invention.

FIG. 2A is a schematic view of the steps of the process of FIG. 2 havingtwo flow paths to accommodate initial separation and processing ofdifferent types of glass.

FIG. 3 is a schematic view of the steps of another alternativeembodiment of the process of the present invention.

FIG. 4 is a diagrammatic side section view of the vibratory breaker ofthe present invention.

FIG. 5 is a top plan view of the vibratory breaker of FIG. 4.

FIG. 6 is a section view of the vibratory breaker through the linesVI--VI of FIG. 4.

FIG. 7 is a front section view of the vibratory breaker through thelines VII--VII of FIG. 4.

FIG. 8 is a side section view of a typical television tube.

FIG. 9 is a schematic view of a preferred materials handling system fordelivering recyclable materials to the vibratory breaker.

FIG. 10 is a schematic view of the initial breaking and separation stepsof the process of FIGS. 1-3.

FIG. 11 is a schematic view of the cleaning and rinsing steps of theprocess of FIGS. 1-3.

FIG. 12 Is a schematic view of the primary crushing step of the processof FIGS. 1-3.

FIG. 13 is a schematic view of the sampling step shown in FIGS. 1 and 2.

FIG. 14 is a schematic showing the process options with respect toseparation and use of glass types.

FIG. 15 is a graph showing the target size distribution of the glassduring various stages of the process.

FIG. 16 is a graph showing the glass composition of panel and funnelglass.

FIG. 17 is a graph showing the relationship between the specific gravityof panel and funnel glass and the cumulative float percentage in theglass type separation step.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

FIGS. 1 through 14 illustrate the various embodiments of the process andapparatus of the present invention. The process of the present inventionwill be described in terms of separating the glass from the nonglasscomponents of television, or TV, picture tubes and the furtherprocessing of the liberated glass. As shown in FIG. 8, a typical TV tubeincludes a panel section 2 and a funnel section 4. In the panel section2, progressing from the front to the back (right to left in the Figure),is the screen 8, a layer of phosphor and other coatings and a metalshadow mask 5. In the neck 6 of the funnel section, are deflectionelectrodes 7, having metal parts, a copper focusing grid 3 and anelectron gun 9, encapsulated in a ceramic housing. Stainless steelstraps 11 surround the neck 6. Those skilled in the art will recognizethat the process and apparatus described herein can be used to separateglass and nonglass components of other kinds of articles made of suchinterconnected materials. In addition, glass alone may be processed bythe techniques of the present invention for sizing, cleaning andseparation of glass types as desired.

Referring to FIG. 1, waste glass including reject whole and broken TVtubes and/or shards of glass from various glass making operations aretransferred to a vibratory breaker 10 wherein the glass components ofthe TV tubes are liberated from the nonglass components and broken intocoarse pieces of a first size range. Thereafter, the broken glass andthe nonglass components are separated. Fine magnetic materials can beseparated by means of a magnetic conveyor 16. Fine nonmagnetic materialssuch as paper, plastic and light density nonmagnetic metals can beseparated by air classification. Large nonglass parts, such as theelectron gun and ceramics can be removed by hand.

The coarse glass pieces are then crushed again, preferably in a primaryvibratory crusher 20, to a second desired size range. If desired, thepanel glass may be separated from the funnel glass at this time, asshown in FIG. 2. The glass is then cleaned in a chemical bath 26 toremove coatings from the glass surface. The cleaning and rinsing stepsmay be done earlier in the process, prior to the further crushing of thecoarse glass, as shown in FIG. 3, or after further crushing as shown inFIGS. 1 and 2. Following the cleaning step, the glass is rinsed,preferably in a cascade rinser 28, and passed to a storage bin 30 foreventual mixture with raw materials for new glass for use in making newglass components. A glass sampler 40 may be provided to sample andanalyze the glass composition prior to use. In an optional step, theglass may pass to a secondary crusher 42 to be further reduced to athird size range either prior to passage to the storage bins 30 orbefore mixture with glass raw materials in a furnace. FIG. 14 shows thepreferred target size distributions of the glass at each stage of theprocess.

Each step of the process will now be described in more detail.

VIBRATORY BREAKING

Referring to FIGS. 1 and 8, shards of glass, broken and whole glassarticles and broken and whole reject TV tubes or similar glass andnonglass composite articles or combinations thereof are withdrawn fromone or more elevated receiving hoppers or bins 12 by a vibratory feederor a belt feeder to a belt conveyor 14 for transfer to a vibratorybreaker 10, such as the one shown in FIGS. 4-7. The purpose of thebreaker 10 is to liberate the glass from the nonglass components byreducing the glass to a manageable size without production ofsignificant quantities of fines. It has been found that pieces within arange of less than about six inches are manageable. The vibratorybreaker 10 creates a predetermined and controlled vibrating action whichcauses the glass to break but does not reduce or break the nonglasscomponents such as the core, electron guns, metal masks and bindingstraps. Significantly, the vibrating action is such that it does notcrush the ceramic components of the TV tubes. The physicalcharacteristics of ceramics and glass are very close. Separating the twoby known processes is very difficult. A frequency of vibrations ofbetween about 900 to about 1800 cycles per minute and a stroke lengthranging from 1/8 to about 1/2 inches with acceleration forces of 3 to 15G are preferred. Tests have shown that a frequency of 1800 cycles perminute, a stroke length of 3/16 inch and an acceleration of 14.3775 Gare successful in separating glass and nonglass and in breaking theglass to the desired manageable size. The vibrations can be adjusted fordifferent types of feed stock.

The vibratory breaker 10 is a modified lumpbreaker attrition millsimilar to those used commercially to reduce the size of no-bake sandlumps to the original grain size. The decks have been modified and thechanneling structures have been added to accommodate the presentinvention. Referring to FIGS. 4-7, the vibratory breaker 10 includes astepped screen deck 70 having an elevated surface 72 and a lower surface74. The depth of the step in the screen deck 70 between the elevated andlower surfaces 72, 74, is about 8 to 15 inches in the preferredembodiment of the breaker 10. The step permits the whole TV tubes tofall face down onto the lower surface 74. The elevated and lowersurfaces each include projections 75 to provide impact surfaces on thedeck 70 and holes 76 through which glass of a predetermined size willfall when the vibrations break the glass. The holes are sized so thatlarger glass pieces and the nonglass components will not fall throughthem. An inlet 78 leads to the elevated surface 72 of the screen deck70. A wall 80 on the lower surface 74 of the screen deck directs thenonglass and any large glass components to a first outlet 82. One end ofthe wall 80 is adjacent the step and the other end is adjacent theoutlet 82.

A plate deck 84 lies beneath the screen deck 70 and receives brokenglass through the holes 76. A wall 86 on the plate deck 84 directs theflow of broken glass to a second outlet 88. One end of the wall 86 isadjacent the outlet 88.

A dust collector 90 is preferably operatively connected to the vibratorybreaker 10 to remove any fines produced in the coarse breaking of theglass. Fines are particles smaller than about 28 mesh. The plate deck 84may also have very fine holes 92 (slightly larger than about 28 mesh) sothe fines fall through the plate deck 84 to a bottom deck 94 where theyare discarded to a waste bin or diverted away from the larger pieces ofrecyclable glass. The fines are preferably removed because treating thefines in the chemical bath significantly increases the costs of theoverall process.

The larger glass pieces and the nonglass components flow across thelower surface 74 of the screen deck 70, out of outlet 2 to a firstchannel 96 in a vibratory conveyor 18. The smaller pieces of glass flowacross plate deck 84, out of outlet 88 to a second channel 98 in thevibratory conveyor 18. The channels may be side by side, separated by apartition or wall 100. Alternatively, one of the channels may be abovethe other. The large, heavier nonglass components, such as the ceramiccomponents and the electron gun may be removed by hand while movingalong the conveyor as shown in FIG. 9.

In the most simple embodiment, there may be only one channel wherein allof the broken glass and nonglass components would progress together.

SEPARATION OF GLASS AND NONGLASS COMPONENTS

An air mag separator, or vibratory classifier, is preferably employed atthis stage to remove light weight waste that has a large surface area toweight ratio; such as, paper, metal straps, buttons, fabric, andplastic, from the stream by air classification. Vibratory actiontogether with high velocity, low pressure air fluidize and stratifymaterial in a known manner according to differences in the terminalvelocity of particles. Materials move along a conveyor by vibratoryaction with high density material settling to the bottom of a trough inthe apparatus. A high velocity (10,000 Ft/Min. to 15,000 Ft/Min. from4,000 to 8,000 SCFM per foot of width) of low pressure air stream isdirected through the material. The material is conveyed into theairstream. Heavy material falls to a secondary separator surface.Lighter material is carried by the air stream to another conveyor fordischarge to a waste bin. The magnetic belt 16 passes above the conveyorto draw any magnetic waste and direct it to a receiving bin 24. Othernonglass waste is directed to a second receiving bin 25. Airclassification systems, air mag separators and magnetic belts arecommercially available.

As shown in FIG. 9, the coarse broken glass remaining is preferablydirected to a screen deck 32 having holes 34 of about 28 mesh, sized topermit the glass fines to fall through the holes 34 to remove the finesfrom the stream of broken class. The coarse broken glass which does notfall through the holes 34 in the screen deck 32 is directed on tofurther processing. The means of removing fines via the screen deck 32may be used instead of or in addition to the fines removal deck in thevibratory breaker 10.

GLASS SIZING

At this stage, the process may take several alternative directions. Asshown in FIG. 1, the coarse glass may be directed to a primary vibratorycrusher 20 where the glass is further reduced in size to pieces nolarger than about 4 inches. The vibratory crusher 20 may be any suitablecommercially available device of this type, such as an impact crusherused to crush stone or various types of ores. A hammermill is one typeof impact crusher. Generally, its design is a box with an inlet locatedat its top for gravity fed material to be crushed and a discharge at itsbottom. A driven shaft is located between the inlet and outlet which hasa series of swinging bars called hammers that are located radially alongits length. They are attached to the shaft with a pivoting joint.Material to be crushed is impacted by the centrifugal force of thesehammers which also throw material against impact plates.

In the primary vibratory crusher 20, it is possible to separate thefunnel glass from the panel glass. The funnel glass will be liberatedfirst because of its greater friability. Panel glass is thicker andstronger. The separation can be optimized by adjusting the combinationof the frequency of the vibrations and stroke (5/16" 1/8×3/8≈900 R.P.M.)to the friability of the types of glass being processed. Screens can beused to separate the glass into two size fractions. As mentioned above,the screens can also further reduce the amount of fines in the stream. Acrude separation of this type can also be carried out in the vibratorybreaker 10. The funnel glass breaks first into smaller pieces which fallthrough holes 76 in the lower surface 74 of screen deck 70. The panelglass breaks into larger pieces which stay on surface 74 and exitthrough outlet 82. The nonglass components are removed and the largerpieces of panel glass continue on through the process. Furtherrefinement after an initial separation of glass types in the breaker 10recommended if a substantially pure stock of at least one type of glassis desired. If an initial separation occurs at the vibratory breaker 10or at the primary crusher 20, there will be two streams of glassprogressing through the process after such initial separation process asshown in FIG. 2A.

FIG. 3 illustrates an alternative direction for process. Followingseparation of the coarse glass from the nonglass components, but priorto further size reduction in the primary crusher 20, the coarse glassmay be cleaned by immersion in a chemical bath 26 for removal of thecoatings or may first pass through a thermal process to remove specificorganic coatings. Any suitable heat treatment sufficient to melt aspecified organic coating without melting the glass to ease the removalof the coating from the glass surface will suffice.

GLASS CLEANING AND RINSING

Chemical bath 26 is preferably a circular vibratory conveyor similar tothose typically used for despruing and sorting but having a trough ofsufficient depth to hold both the liquid and glass pieces. If twostreams of glass are being maintained because of an initial separationof glass type, the bath 26 will have two separate channels to maintainthe integrity of the two glass streams. This design permits veryeffective scrubbing of the glass while using a minimum amount ofcleaning fluid. As a result, less effluent must be treated for disposal.

A suitable fume hood is provided to remove hazardous or irritating fumesfrom the bath area. The chemicals used in the bath depends on thecoatings to be removed from the surface of the glass. In the process forremoving coatings from the funnel and panel glass of TV tubes, the bathis preferably an acid and, more preferably, an ammonium bifluoride or ahydrofluoric acid bath. An ammonium bifluoride solution, preferablyhaving a concentration of about 1.5%, has been found to work well. Theammonium bifluoride is preferred due to the known hazards ofhydrofluoric acid. The preferred residence time will vary up to about 10minutes, and preferably, will be between about 5 to 10 minutes. Timeperiods longer than 10 minutes are possible but it has been found that,when coatings are to be removed from the glass of TV tubes with ammoniumbifluoride or hydrofluoric acid, the glass is clean within a residencetime of 10 minutes.

As shown in FIG. 11, an optional second bath 27 containing, for example,nitric acid for use in removing the frit bonding between the panel glassand funnel glass from TV tubes, may be used. Nitric acid may be mixedwith the hydrofluoric acid or ammonium bifluoride solutions.

Following the chemical cleaning treatment, the glass is rinsed,preferably in a cascade washer 28. Any suitable known rinsing procedurewill suffice, such as simply spraying the glass with water or some othersuitable known rinsing agent. It has been found, however, that acountercurrent rinsing process not only effectively rinses the glass butconserves water use. Sumps 36, D1 to D6 in FIG. 11, collect the waterfor reuse. Thus, there is a minimal amount of waste water to treat. Thechemically cleaned glass is drained of the cleaning solution, which isreturned to the chemical bath 26. The drained glass enters the cascadewasher 28 in a known manner at the upstream end 31 of the washer 28. Thefresh water enters at the down stream end 33 of the cascade washer 28and flows upstream so that the rinse water which first contacts thedrained, chemically treated glass as it comes in from the chemical bath26 has already passed over treated glass removing some of the coatings.The further downstream the glass flows, the cleaner (or lessconcentrated) the rinse water is, with the last rinse being just cleanwater. It has been found that the amount of water used in the rinse isnot as important as the number of rinses. In FIG. 11, five rinsing stepsare indicated, R1 to R5. The number of rinses can vary.

Studies were performed to evaluate methods of removing the coatings fromthe glass surfaces and to quantify the cleaning solution and rinse waterrequirements. The glass was cleaned by agitating the glass pieces invarious cleaning solutions for 3 to 30 minutes under differentconditions to establish equipment design parameters and the efficacy ofthe system.

The treatability study results are presented in Table 1.

                                      TABLE 1                                     __________________________________________________________________________    GLASS CLEANING TREATMENT TEST DATA                                                                        PERCENT                                           TEST                                                                              TEST       DESCRIPTION OF                                                                             WEIGHT LOSS                                       NO. DESCRIPTION                                                                              EFFECT ON GLASS                                                                            THROUGH CLEANING                                  __________________________________________________________________________     1. 20% sodium hydroxide                                                                     Aluminum coating                                                                           See Test #6                                           with 5 minutes of mix-                                                                   on panel glass is                                                  ing at ambient temper-                                                                   largely removed.                                                   ature.     Funnel glass                                                                  pieces have some                                                              graphite coating                                                              remaining and                                                                 iron oxide coating                                                            is unaffected                                                                 visually.                                                       2. 20% sodium hydroxide                                                                     Aluminum coating                                                                           1.3                                                   solution with 10                                                                         on panel glass is                                                  minutes of mixing at                                                                     removed. Funnel                                                    ambient temperature.                                                                     glass pieces have                                                             some graphite coat-                                                           ing remaining and                                                             visually the iron                                                             oxide coating is                                                              unaffected.                                                     3. 20% sodium hydroxide                                                                     Aluminum coating                                                                           1.0                                                   solution with 5                                                                          on panel glass is                                                  minutes of mixing at                                                                     completely removed.                                                120° F.                                                                           Iron oxide coating                                                            on funnel glass                                                               pieces begins to                                                              pit and hence be                                                              very slightly                                                                 removed.                                                         4.                                                                              20% sodium hydroxide                                                                     Aluminum coating on                                                                        1.0                                                   solution at 120° F. with                                                          panel glass is                                                     10 minutes for mixing.                                                                   completely removed.                                                           Iron oxide coating                                                            on funnel glass pieces                                                        has pits open to                                                              glass surface; slight                                                         removal of iron oxide                                                         coating.                                                        5. 20% sodium hydroxide                                                                     Aluminum coating on                                                                        3.0                                                   150° F. with 30 minutes                                                           on panel glass is                                                  for mixing.                                                                              completely removed.                                                           Funnel glass has                                                              partial iron oxide                                                            removal. Mixing                                                               has broken glass into                                                         smaller pieces.                                                 6. Glass from Test #1                                                                       Both panel glass and                                                                       7.2                                                   rinsed in tap water;                                                                     funnel glass pieces                                                and mixed 5 minutes                                                                      are cleaned. Funnel                                                in 15% hydrofluoric                                                                      glass surface has a                                                acid solution at                                                                         texture. Panel glass                                               at ambient pieces have a few                                                  temperature.                                                                             spots of white residue                                                        in recessed areas.                                              7. 5 minutes of mixing                                                                      Panel glass has some                                                                       0.64                                                  in 15% nitric acid                                                                       aluminum coating removed                                           solution at ambient                                                                      (one piece has consider-                                           temperature.                                                                             able coating left).                                                           Funnel glass pieces                                                           have some graphite                                                            coating remaining                                                             visually the iron oxide                                                       coating is unaffected.                                          8. Mix 10 minutes in 15%                                                                    Aluminum coating on                                                                        0.88                                                  nitric acid solution                                                                     panel glass is                                                     at ambient completely removed.                                                temperature.                                                                             Iron oxide coating on                                                         funnel glass visually                                                         is unaffected. Some                                                           graphite coating                                                              remains.                                                        9. Mix for 5 minutes                                                                        Aluminum coating on                                                                        1.0                                                   in 15% nitric acid                                                                       panel glass is                                                     solution at 120° F.                                                               completely removed.                                                           Iron oxide and                                                                graphite coatings on                                                          funnel glass are                                                              unaffected visually.                                           10. Mix for 10 minutes                                                                       Aluminum coating on                                                                        2.7                                                   in 15% nitric acid                                                                       panel glass is                                                     solution at 120° F.                                                               completely removed.                                                           Iron oxide and                                                                graphite coatings                                                             on funnel glass                                                               are unaffected.                                                11. Mix 5 minutes in 15%                                                                     Funnel glass pieces                                                                        6.8                                                   hydrofluoric acid                                                                        are clean and clear                                                solution at ambient                                                                      with textured surface.                                             temperature.                                                                             Smoked gray panel glass                                                       pieces are clean with                                                         white residue in                                                              recessed areas.                                                12. Mix 10 minutes in 15%                                                                    Funnel glass pieces                                                                        7.3                                                   hydrofluoric acid                                                                        are clean and clear                                                at ambient with a textured                                                    temperature.                                                                             surface. Smoked                                                               gray panel glass                                                              pieces are clean                                                              with white residue                                                            in recessed areas.                                             13. Mix for 5 minutes at                                                                     Funnel glass pieces                                                                        97.8                                                  ambient temperature                                                                      are clean and clear                                                in solution of 15%                                                                       with a textured                                                    hydrofluoric acid.                                                                       surface. Smoked                                                               gray panel glass                                                              pieces are clean                                                              with only a small                                                             amount of a white                                                             residue in a couple                                                           of recessed areas.                                             14. Mix for 10 minutes at                                                                    Funnel glass pieces                                                                        9.2                                                   ambient temperature                                                                      are very clean and                                                 in solution of 15%                                                                       clear with a textured                                              hydrofluoric acid.                                                                       surface. Smoked gray                                                          panel glass pieces                                                            are clean with only                                                           a small amount of a                                                           white residue in a                                                            couple of recessed                                                            areas.                                                         15. Mix for 3 minutes at                                                                     Funnel glass pieces                                                                        3.1                                                   ambient temperature                                                                      are clean and clear                                                in solution of 14%                                                                       with a textured or                                                 nitric acid and 15%                                                                      pitted surface.                                                    hydrofluoric acid                                                                        Smoked gray panel                                                             glass pieces are                                                              clean with a white                                                            residue in recessed                                                           areas.                                                         16. Mix at ambient                                                                           Funnel glass pieces                                                                        0.73                                                  temperature for 5                                                                        with graphite and iron                                             minutes in phosphate                                                                     oxide coatings are                                                 ammonia bifluoride                                                                       visually unaffected.                                               cleaning mixture.                                                                        Panel glass pieces are                                             (100% as received).                                                                      cleaned.                                                       17. Mix for 5 minutes                                                                        Graphite and iron oxide                                                                    1.2                                                   in 15% acid strength                                                                     coatings on the funnel                                             solution prepared                                                                        glass pieces are                                                   using a blend of 90%                                                                     unaffected visually.                                               conc. nitric acid                                                                        Coating on panel glass                                             plus 10% of                                                                              pieces is removed.                                                 phosphate ammonia                                                             bifluoride mixture.                                                       18. Mix at ambient                                                                           Graphite and iron oxide                                                                    0.59                                                  temperature for 5                                                                        coatings on funnel glass                                           minutes in 15% acid                                                                      pieces are visually                                                strength solution                                                                        unaffected. Aluminum                                               prepared using a                                                                         coating on panel glass                                             blend of 90% conc.                                                                       is completely removed.                                             hydrochloric acid                                                             plus 10% of                                                                   phosphate ammonia                                                             bifluoride mixture.                                                       19. Mix for 5 minutes at                                                                     Funnel glass pieces                                                                        1.4                                                   ambient temperature                                                                      are clean and clear                                                in solution of 71/2T                                                                     with a textured                                                    hydrofluoric acid and                                                                    surface. Smoked gray                                               71/2% nitaric acid                                                                       panel glass pieces                                                            are clean.                                                     20. Mix for 5 minutes at                                                                     Funnel glass pieces                                                                        3.5                                                   ambient temperature                                                                      are clean and clear                                                in solution of 3%                                                                        with a textured                                                    hydrofluoric acid                                                                        surface. Smoked gray                                               and 12% nitric acid.                                                                     panel glass pieces are                                                        clean.                                                         21. Mix for 5 minutes at                                                                     Funnel glass pieces                                                                        1.1                                                   ambient temperature                                                                      are very clean and clear                                           in solution of 1%                                                                        with a textured                                                    hydrofluoric acid                                                                        surface. Smoked gray                                               and 14% nitric acid.                                                                     panel glass pieces are                                                        clean.                                                         22. Mix for 5 minutes at                                                                     Funnel glass pieces                                                                        1.3                                                   ambient temperature                                                                      are very clean and clear                                           in solution of 1%                                                                        with a textured                                                    hydrofluoric acid                                                                        surface. Smoked gray                                               and 9% nitric acid.                                                                      panel glass pieces are                                                        clean.                                                         23. Mix for 5 minutes at                                                                     Funnel glass pieces                                                                        1.5                                                   ambient temperature                                                                      are very clean and clear                                           in solution of 1%                                                                        with a textured                                                    hydrofluoric acid                                                                        surface. Smoked gray                                               and 5% nitric acid.                                                                      panel glass pieces are                                                        clean.                                                         24. Mix for 5 minutes                                                                        Funnel glass pieces                                                                        0.73                                                  in a 1.5% ammonium                                                                       are very clean and clear                                           bifluoride solution.                                                                     with a textured                                                               surface. Smoked gray                                                          panel glass pieces are                                                        clean.                                                         25. Mix for 5 minutes                                                                        Funnel glass pieces                                                                        1.35                                                  in a 5% ammonium                                                                         are very clean and clear                                           bifluoride solution.                                                                     with a textured                                                               surface. Smoked gray                                                          panel glass pieces are                                                        clean.                                                         26. Mix for 10 minutes                                                                       Funnel glass pieces                                                                        1.98                                                  in a 10% ammonium                                                                        are very clean and clear                                           bifluoride solution.                                                                     with a textured                                                               surface. Smoked gray                                                          panel glass pieces are                                                        clean.                                                         __________________________________________________________________________

These results indicate that sodium hydroxide and nitric acid removedonly the aluminum coating. The iron oxide coating is virtuallyunaffected by sodium hydroxide or nitric acid treatment, even at hightemperatures.

The cleaning solutions containing from 1 to 15% hydrofluoric acid wereeffective in removing the internal and external coatings completely fromthe glass surfaces. The 1% hydrofluoric acid solution cleaned the glasssurfaces within 5 minutes with agitation. The total reductions in theweight of the glass which resulted from cleaning with 1% and 15%hydrofluoric acid solutions were 1.5% and 6.8%, respectively. The weightloss due to cleaning increased proportionally as acid concentration andagitation time increased. The hydrofluoric acid alone was as effectiveas the mixture of hydrofluoric acid and nitric acid.

The treatability study results indicate that the ammonium bifluoridesolution also removed the internal and external coatings from the paneland funnel glass with 5 minutes of agitation. The total weight losses ofthe glass during the cleaning operation with the 1.5%, 5%, and 10%ammonium bifluoride solutions were 0.7%, 1.3%, and 2.1%, respectively.These weight losses were significantly lower than those observed whencleaning with hydrofluoric acid.

Treatability studies were then performed to determine the cleaning bathlife and the rinse water requirements. Various cleaning solutions wereprepared and used until exhaustion. The cleaning solutions consisted of1, 3, and 5% hydrofluoric acid solutions, a mixture of 1% hydrofluoricacid and 9% nitric acid, a mixture of 1% hydrofluoric acid and 5% nitricacid, and a 1.5% ammonium bifluoride solution. Approximately 100 gramsof glass were added to 100 ml of each cleaning solution. After a 5minute agitation period, the cleaning solution was decanted, and thecleaned glass samples were rinsed and dried. Another weighed incrementof uncleaned broken glass was then added to the recovered cleaningsolution and agitated for 5 minutes. Successive increments of uncleanedglass were cycled through the recovered cleaner until coating removalfailed. The results indicate that when cleaning failed, the iron oxidecoating remained on the glass. The tests also demonstrated that themixture of hydrofluoric and nitric acid did not have a longer cleaninglife or a reduced cleaning time as compared to the hydrofluoric acidalone. After three cleaning cycles using 1% hydrofluoric acid or 1.5%ammonium bifluoride i.e., after cleaning 30 grams of glass with 100 mlof the cleaning solution, the solutions were partially spent and thefourth batch could not be completely cleaned. The cleaning solutionscontaining 3% or 5% hydrofluoric acid were spent after 7 and 8 cycles,respectively. The test results are summarized in Tables 2 to 11.

                  TABLE 2                                                         ______________________________________                                        CLEANING SOLUTION RECYCLE TEST DATA                                           1% HF + 9% HNO.sub.3                                                                 Percent Weight                                                         Cycle  Loss         Glass Description                                         ______________________________________                                        1.     0.92         Both funnel and panel pieces are                                              clean.                                                    2.     1.6          Both funnel and panel pieces are                                              clean.                                                    3.     1.6          Funnel glass is 95% clean; panel                                              pieces are clean.                                         4.     1.5          Funnel glass is 50% clean; panel                                              pieces are clean.                                         5.     1.0          Funnel glass is 30% clean; panel                                              pieces are clean.                                         ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                        CLEANING SOLUTION RECYCLE TEST DATA                                           1% HF + 9% HNO.sub.3 (REPEATED TEST)                                                 Percent Weight                                                         Cycle  Loss         Glass Description                                         ______________________________________                                        1.     1.4          Both funnel and panel pieces are                                              clean.                                                    2.     3.7          Both funnel and panel pieces are                                              clean.                                                    3.     1.4          Funnel glass is 95% clean; panel                                              pieces are clean.                                         4.     0.86         Funnel glass is 95% clean; panel                                              pieces are clean.                                         5.     0.96         Funnel glass is 10% clean; panel                                              pieces are clean.                                         ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                        CLEANING SOLUTION RECYCLE TEST DATA                                           1% HF + 5% HNO.sub.3 (REPEATED TEST)                                                 Percent Weight                                                         Cycle  Loss         Glass Description                                         ______________________________________                                        1.     1.5          Both funnel and panel pieces are                                              clean.                                                    2.     0.77         Both funnel and panel pieces are                                              clean.                                                    3.     1.4          Both funnel and panel pieces are                                              clean.                                                    4.     1.5          Funnel glass is 90% clean; panel                                              pieces are clean.                                         5.     1.0          Funnel glass is 85% clean; panel                                              pieces are clean.                                         ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                        CLEANING SOLUTION RECYCLE TEST DATA                                           1% HF + 9% HNO.sub.3 (REPEATED TEST)                                                 Percent Weight                                                         Cycle  Loss         Glass Description                                         ______________________________________                                        1.     2.0          Both funnel and panel pieces are                                              clean.                                                    2.     1.5          Both funnel and panel pieces are                                              clean.                                                    3.     1.3          Funnel glass is 55% clean; panel                                              pieces are clean.                                         4.     0.63         Funnel and panel pieces are clean.                        5.     0.33         Funnel glass is 50% clean; panel                                              pieces are clean.                                         ______________________________________                                    

                  TABLE 6                                                         ______________________________________                                        CLEANING SOLUTION RECYCLE TEST DATA                                           1% HF + 2.5% HNO.sub.3                                                               Percent Weight                                                         Cycle  Loss         Glass Description                                         ______________________________________                                        1.     0.96         Both funnel and panel pieces are                                              clean.                                                    2.     0.87         Both funnel and panel pieces are                                              clean.                                                    3.     0.37         Funnel glass is 50% clean; panel                                              pieces are clean.                                         4.     0.87         Funnel glass is 50% clean; panel                                              pieces are clean.                                         5.     0.73         Funnel glass is 50% clean; panel                                              pieces are clean.                                         ______________________________________                                    

                  TABLE 7                                                         ______________________________________                                        CLEANING SOLUTION RECYCLE TEST DATA                                           1% HF                                                                                Percent Weight                                                         Cycle  Loss         Glass Description                                         ______________________________________                                        1.     1.5          Both funnel and panel pieces are                                              clean.                                                    2.     1.3          Both funnel and panel pieces are                                              clean.                                                    3.     0.71         Both funnel and panel pieces are                                              clean.                                                    4.     0.74         Funnel glass is 75% clean; panel                                              pieces are clean.                                         5.     0.63         Funnel glass is 30% clean; panel                                              pieces are clean.                                         ______________________________________                                    

                  TABLE 8                                                         ______________________________________                                        CLEANING SOLUTION RECYCLE TEST DATA                                           1.5% AMMONIUM BIFLUORIDE                                                             Percent Weight                                                         Cycle  Loss         Glass Description                                         ______________________________________                                        1.     0.73         Both funnel and panel pieces are                                              clean                                                     2.     1.12         Both funnel and panel pieces are                                              clean                                                     3.     1.2          Both funnel and panel pieces are                                              clean                                                     4.     1.33         Funnel glass is 25% clean; panel                                              pieces are clean.                                         ______________________________________                                    

                  TABLE 9                                                         ______________________________________                                        CLEANING SOLUTION RECYCLE TEST DATA                                           1% HF (REPEATED TEST)                                                                Percent Weight                                                         Cycle  Loss         Glass Description                                         ______________________________________                                        1.     1.3          Both funnel and panel pieces are                                              clean.                                                    2.     1.5          Both funnel and panel pieces are                                              clean.                                                    3.     0.74         Both funnel and panel pieces are                                              clean.                                                    4.     0.72         Funnel glass is 25% clean; panel                                              pieces are clean.                                         5.     0.84         Funnel glass is 80% clean; panel                                              pieces are clean.                                         6.     1.6          Funnel glass is 25% clean; panel                                              pieces are clean.                                         ______________________________________                                    

                  TABLE 10                                                        ______________________________________                                        CLEANING SOLUTION RECYCLE TEST DATA                                           3% HF                                                                                Percent Weight                                                         Cycle  Loss         Glass Description                                         ______________________________________                                        1.     2.6          Both funnel and panel pieces are                                              clean.                                                    2.     1.2          Both funnel and panel pieces are                                              clean.                                                    3.     1.8          Both funnel and panel pieces are                                              clean.                                                    4.     1.0          Both funnel and panel pieces are                                              clean.                                                    5.     1.2          Both funnel and panel pieces are                                              clean.                                                    6.     1.2          Both funnel and panel pieces are                                              clean.                                                    7.     1.7          Both funnel and panel pieces are                                              clean.                                                    8.     1.2          Funnel glass is 75% clean; panel                                              pieces are clean.                                         9.     1.2          Funnel glass is 10% clean; panel                                              pieces are clean.                                         ______________________________________                                    

                  TABLE 11                                                        ______________________________________                                        CLEANING SOLUTION RECYCLE TEST DATA                                           5% HF                                                                                Percent Weight                                                         Cycle  Loss         Glass Description                                         ______________________________________                                        1.     4.3          Both funnel and panel pieces are                                              clean.                                                    2.     1.7          Both funnel and panel pieces are                                              clean.                                                    3.     1.7          Both funnel and panel pieces are                                              clean.                                                    4.     1.7          Both funnel and panel pieces are                                              clean.                                                    5.     1.5          Both funnel and panel pieces are                                              clean.                                                    6.     1.0          Both funnel and panel pieces are                                              clean.                                                    7.     1.3          Both funnel and panel pieces are                                              clean.                                                    8.     1.4          Both funnel and panel pieces are                                              clean.                                                    9.     1.4          Funnel glass is 95% clean; panel                                              pieces are clean.                                         10.    1.5          Funnel glass is 98% clean; panel                                              pieces are clean.                                         11.    2.7          Both funnel and panel pieces are                                              clean.                                                    12.    2.7          Funnel glass is 5% clean; panel                                               pieces are clean.                                         13.    1.7          Funnel glass is 2% clean; panel                                               pieces are clean.                                         ______________________________________                                    

In addition to evaluating methods of removing the coatings, and toensure that the sequence of equipment was effective, studies wereperformed to determine the quantity of water required to adequatelyrinse the glass pieces after immersion in the cleaning solution. Thecleaned glass was rinsed with 100 ml of tap water per 100 grams ofglass. The first and second cycles of rinse water contained 209 mg/L and23 mg/L fluoride, respectively. Since spray rinsing and more vigorousagitation are believed to provide better rinsing in a commercial settingthan that of the batch/soak rinsing procedure used in laboratorytreatment schemes, the rinsing of the glass pieces in a volume of waterequal to the volume of cleaner used is concluded to be adequate forremoving the excess cleaner from the glass. Based on the treatabilitystudy results, the following conclusions can be derived: hydrofluoricacid or a mixture of hydrofluoric acid and nitric acid or ammoniumbifluoride solution will adequately clean the glass in the sequence ofthe equipment selected for the system; the presence of nitric acid doesnot improve the cleaner life (but will, as stated below, dissolve thelead frit between the panel and funnel glass); and the weight loss fromcleaning increases with the increase in the cleaning solutionconcentration.

In addition to the graphite coating, the funnel glass of TV tubessometimes has a small area which is colored with a red dye on theoutside surface. The dye is an inorganic red pigment in a solvent. Thered dye is a coating applied as an aid to sealing the evacuation holewhen air is evacuated from the tube. Since this red dye is moredifficult to remove than either the graphite or the iron oxide coatingson the funnel glass, treatability studies were performed to evaluate thefeasibility of removing it. Cleaning duration versus dye remaining ispresented in Table 12. Approximately 50% of the dye remained aftercleaning for 5 minutes with 1% hydrofluoric acid. Agitation during theperiod of time the pieces of glass are exposed to the hydrofluoric acidimproves the amount of dye removed. Agitation may be continuous orintermittent. Agitation for 20 minutes in hydrofluoric acid removedsubstantially all of the dye.

                  TABLE 12                                                        ______________________________________                                        1% HF CLEANING OF FUNNEL GLASS RED                                            COLORED COATED AREAS                                                                            Description of                                                                Effect on Glass                                             ______________________________________                                        1.  Funnel glass pieces contain-                                                                      Funnel glass has iron oxide                               ing red colored areas soak                                                                        completely removed. Red                                   in 100 ml 1% HF for 5 minutes.                                                                    colored area is approxi-                                                      mately 50% clean.                                     2.  Agitate the glass and cleaner of                                                                  Red colored area is                                       item No. 1 above for 5 minutes.                                                                   approximately 75% clean.                              3.  Re-agitate the glass and                                                                          Red colored area is                                       cleaner solution of item above                                                                    approximately 95% clean.                                  No. 2 for an additional 5 minutes.                                        4.  Re-agitate the glass and                                                                          Red colored area is                                       cleaner solution of item                                                                          approximately 99% clean.                                  No. 3 for 5 minutes additional                                                time.                                                                         Analyses of glass and cleaner:                                                Weight of glass tested, grams                                                                     89.9                                                      Percent weight loss through cleaning                                                              3.8                                                       Used cleaner (after 15 minute)                                                                    <1                                                        sludge volume, %                                                          ______________________________________                                    

When the picture tubes are broken, the resulting glass pieces are eitherpanel glass, funnel glass, or a mixture of panel and funnel glass joinedby frit material. Since thorough separation of the panel glass andfunnel glass would be advantageous, a procedure for removing the fritwas investigated.

It was found that the frit was completely dissolved within 10 minuteswhen the glass pieces with the exposed frit were agitated in a 12%nitric acid solution. Agitation may be continuous or intermittent.

The results of the glass cleaning treatability study indicated thateither the 1% hydrofluoric acid or 1.5% ammonium bifluoride cleaningsolution could remove the coatings completely for three cleaning cycles.The process is suitable for either continuous or batch processingsubject to the performance of the cleaning solutions and therequirements of the cleaning process. The cleaning solutions are notcompletely spent after three cycles, and they might be able to removethinner coatings for additional cycles. A cycle consisted of cleaning100 grams of glass agitated with 100 ml of cleaning solution.

SECONDARY CRUSHING

Following the cleaning and rinsing steps, the glass pieces may befurther screened to make sure the pieces are all appropriately sized.Further crushing of the glass to a final desired size before samplingmay be desired. Referring to FIGS. 12 and 15, a secondary crusher 42 ofany suitable known type is provided for reducing the size of the glassto pieces no larger than about 2 inches. The screen 45 would be sized topermit pieces under about 1.5-2 inches to fall through to a conveyor 48.Oversized pieces would be directed to secondary vibratory crusher 42 forsizing to pieces less than 2 inches. The glass would be discharged fromsecondary crusher 42 to the conveyor 48 to join the screened glass fortransfer to either the optional separation process or to storage andlater sampling for analysis. The sized glass may then be melted down andmixed with the raw materials for new glass for use in new products. Itis expected that up to 40% of glass in a new product can be fromrecycled glass.

The secondary crushing is optional. The glass may progress from thecleaning operation directly to sampling and analysis or the furnace foruse.

STORAGE, SAMPLING AND ANALYSIS

The cleaned glass, as shown in FIG. 1, the preferred embodiment, may bemoved along a belt conveyor 38 to a storage bin 30 or may be stored atground level in separate walled containment areas.

Samples can be removed from the storage bin 30 for analysis by means ofany suitable known sampler 40 as illustrated in FIG. 13. The glass isreleased from one of the storage bins 30 to a belt conveyor 41 whichdirects the glass to sampler 40. About 25% of the glass coming fromconveyor 41 is directed to a primary sampler, then to the sample crusher47. The glass released from the sample crusher 47 is split into twostreams. About 10% of the sample exiting the sample crusher 47 goes onto the analyzer. The sample crusher 47 goes on to the analyzer. Theremainder joins the 75% glass fraction from belt conveyor 41 which didnot enter the sampler 40 for storage or melting in a furnace.

A neutron gauge analyzer, similar to those used to analyze coal samples,has been found to work well for glass composition analysis. The analyzerwill measure the compositions of the glass pieces fed into it andprovide that information in any suitable form. The preferred analyzer isa commercially available product which uses a shaking tube samplepresentation technique coupled with two gauges, thermal neutron capturegamma analysis and gamma transmission. Pieces of glass of 2 inches orless are fed into an inlet hopper. The glass is bombarded with thermalneutrons from a radioisotope source. When a neutron is captured by thenucleus of an element in the glass, the nucleus contains excess energy.Gamma energies of one or more wave lengths are emitted from the excitednucleus depending on the element. Gamma rays emitted from each element'snucleus have specified values. The chemical analysis of the glass iscalculated by known techniques on a microprocessor based on the neutroncapture produced Gamma spectra.

FIG. 16 illustrates the difference in the chemical compositions of paneland funnel glass. It is important that glass adhere substantially, ifnot entirely, to the relative compositions established for that type ofglass. Analysis prior to mixing with the raw materials for new glass maybe important.

GLASS SEPARATION

Liberation of funnel glass from the mixed glass is possible by selectivecrushing, taking advantage of the differences in the friability of theglass. When a more reliable separation is desired, the followingtechniques can be used.

Referring to FIGS. 2 and 3, an optional step of separating one of thetypes of glass from the other is provided. The separation step is basedon the difference in density between glass types. FIG. 17 illustratesthe cumulative percentage of glass at certain specific gravities thatwill float on the separation medium preferably used in the separationstep of the present invention.

The specific gravity of panel glass is about 2.7. Slight variations inthe panel glass specific gravity exist among various glass suppliers.The specific gravity of funnel glass is about 2.8-2.9. In wastetelevision tubes, a mixed glass fraction exists constituting both funneland panel glass bonded by a frit. The specific gravity of this fractionis variable, but falls between that of panel and funnel glass.

A dense suspension medium of a recoverable material is used to suspendor float the lower density glass. The other, higher density glass willsink. Suspension mediums which may be employed are usually a watersuspension of a fine high specific gravity material, such as magnetite,an organic liquid or ferro silicones. In the preferred application wherefunnel glass is to be separated from panel glass, the suspension mediumshould have a specific gravity of about 2.7. The specific gravity of thesuspension media is chosen to optimize the separation. A series of testswere conducted to define the parameters of the separation process as itapplies to waste TV tubes.

Tests were conducted to define the characteristics of the glass. Byusing high density organic liquids, mixtures of tetrabromoethane andcommercially available mixtures or suspensions of organic and inorganicliquids, the separating densities were determined. The results are shownin Table 13.

                  TABLE 13                                                        ______________________________________                                        LAB TESTS USING ORGANIC LIQUIDS                                               SPECIFIC        WEIGHT PERCENT                                                GRAVITY FRACTION                                                                              FUNNEL    MIXED    PANEL                                      ______________________________________                                        Float 2.6       0         0        0                                          2.60 × 2.70                                                                             25        0        0                                          2.70 × 2.80                                                                             10        25       0                                          2.80 × 2.84                                                                             0         5        0                                          Sink 2.84       0         0        35                                         ______________________________________                                    

Table 14 sets forth the results of separation studies on mixed glass atthree size levels using high density organic liquids.

                  TABLE 14                                                        ______________________________________                                        LAB TESTS USING TETRABROMOETHANE                                              SAMPLE: MIXED BROKEN GLASS                                                    LIQUID SPECIFIC GRAVITY - 2.84                                                             WEIGHT PERCENT                                                   SAMPLE SIZE AND ID                                                                           FEED       FLOAT    SINK                                       ______________________________________                                        Panel - Plus 2 inch                                                                          50         50                                                  Funnel - Plus 2 inch                                                                         50                  50                                         Panel - 2 inch by 28 mesh                                                                    50         50                                                  Funnel - 2 inch by 28 mesh                                                                   50                  50                                         Panel - Minus 28 mesh                                                                        50         50                                                  Funnel - Minus 28 mesh                                                                       50                  50                                         ______________________________________                                    

The results demonstrate that perfect separation of funnel and panelglass can be achieved. Using samples of as-received glass sized to amaximum size of four inches, the mixed glass separated at gravitiesassociated with the major component of the mixed glass, i.e., panel orfunnel. The tests show that the funnel glass separates from the lighterglass fractions most effectively at a separation gravity in the range ofabout 2.85 to about 2.90, represented as D50 on the yield gravity curvein FIG. 17. In mineral processing, the separating gravity is usuallyreferred to as the D50 point on a performance curve.

The data indicate that the better the funnel glass is separated from themixed glass through selective sizing (i.e., at the vibratory breaker 10and/or the primary crusher 20), the more pure funnel glass is obtained.It has been found further that when the frit is exposed, nitric acidwashing as described above will provide a cleaner funnel fraction.

Although the foregoing tests demonstrate that high density organicliquids function successfully as the separation medium, such liquids maybe too hazardous for commercial scale operations. It is preferredtherefore, to use magnetite or ferro silicon suspended in water. Themagnetite suspension medium of the present invention is a suspension of80% solids. An anionic dispersant, such as ligno-sulfate or ammoniumnaphthalene sulfonic acid condensate polymer is added to the suspensionmedium to provide a low viscosity, pumpable medium having a relativelyhigh density. The dispersant content is about 5% by weight of the solidscontent.

Magnetite water slurries having a solids content of up to about 50% areused in coal processing operations. It is known, however, that when thesolids content is greater that about 40% the slurry becomes too viscousand can't be pumped.

It has been unexpectedly found that the addition of dispersant to themagnetite/water mixture provides a low viscosity, high densitysuspension having about an 80% solids content. The magnetite suspensionof the present invention is pumpable.

Several tests were conducted using commercially available magnetite.Commercial magnetite is available in various grades generally designatedA to E with the mean particle size becoming increasingly finer fromgrade A to grade E. It was found that A grade magnetite was difficult topump but resulted in effective separation. E grade magnetite provided apumpable slurry upon the addition of a dispersing agent.

A preferred media for the separation step is ferro silicon with a highiron content. Ferro silicon, having a specific gravity of 5.0 to 5.5, ishigher in density than magnetite, which has a specific gravity of4.0-5.0.

Referring to FIG. 2, glass passes to the gravity separator 44 followingfurther sizing in the primary vibratory crusher 20. In the embodiment ofthe process where the difference in friability of panel and funnel glassis employed to make an initial separation of the two glass types,following the further sizing of the glass in the primary vibratorycrusher 20, two streams of glass flow to a gravity separator 44. Thepanel rich fraction side of the gravity separator 44 is essentially adry vibratory conveyor. The funnel rich fraction side is equipped as adense media vessel with circulating pumps and discharges for the floatand sink glass fractions. The float fraction will consist of anyremaining panel glass and mixed glass, while the sink fraction willconsist of higher specific gravity funnel glass. In commercialprocessing, it is desirable to insure a pure fraction of funnel glass.The benefit may justify some inefficiencies in the float fraction sothat the sink fraction at best, will not contain any panel glass and atworst, will only contain insubstantial amounts of panel glass. The floatfraction may contain some funnel glass.

The float and sink fractions are fed to a split drain and rinse screen46 to maintain the integrity of the fractions. The glass flows over thescreen, letting most of the suspension media fall through the screen tobe returned to the dense media separating vessel. Some of the suspensionmedium will remain with the glass (estimated to be approximately onepound of media per ton of glass processed).

The rinsed float fraction containing panel and mixed glass is combinedwith the dry fraction of panel rich glass and directed toward theappropriate section of the chemical bath 26. The rinsed sink fraction ofsubstantially pure funnel glass is directed to a second section of thechemical bath 26.

The remaining media will be removed when the fractions progress onto thecleaning and rinsing steps. The chemical bath 26 and the cascade rinse28 are each divided into two sections to maintain the integrity of thefractions. In the embodiment of the process diagrammed in FIG. 3, thecleaning step precedes the separation step. In that embodiment,additional rinsing following dense media separation is provided.

There are several options for glass separation offered by the process ofthe present invention as shown in FIG. 14. The glass separation can bedirected to obtaining a stream of generally pure funnel glass andgenerally pure panel glass by taking advantage of the glass separationtechniques at each step of the process and adjusting the specificgravity of the dense suspension medium accordingly. Alternatively, asecond separation option having one fraction of substantially pure glassand a second fraction of mixed glass can be chosen. Finally, there maybe no need or desire to separate glass types. Under those circumstances,a third option of producing only a fraction of mixed glass is shown. Thevarious glass fractions may be analyzed to determine the compositionbefore directing the fraction onto the furnace for melting and eventualmixture with new glass raw materials.

What is claimed is:
 1. A process comprising:subjecting a feed stock ofwaste materials comprised of articles and portions thereof made of glassand nonglass components, wherein at least portions of said glasscomponents are affixed to at least portions of said nonglass components,to controlled vibrations in a vibrating apparatus at a frequency, impactforce and for a period of time effective for breaking said glasscomponents into pieces of glass of a first size range and for liberatingsaid glass components from said nonglass components; and thereafterseparating said nonglass components present in the feed stock from saidpieces of glass.
 2. The process recited in claim 1 further comprisingremoving glass fines from said pieces of glass.
 3. A processcomprising:subjecting a feed stock of waste materials comprised ofarticles and portions thereof made of glass and nonglass components,articles and portions thereof made of glass, glass shards andcombinations thereof to vibrations in a vibrating apparatus at afrequency, impact force and for a period of time effective for breakingglass components into pieces of glass of a first size range and forliberating said glass components from said nonglass components, at leastsome of said glass being coated; separating any nonglass componentspresent in the feed stock from said pieces of glass; and following saidseparating step, removing the coatings from said pieces of glass.
 4. Theprocess recited in claim 3 further comprising, following said removingstep, the step of rinsing said pieces of glass.
 5. The process recitedin claim 4 wherein aid rinsing step comprises passing said pieces ofglass through a counter current cascade washer.
 6. The process recitedin claim 3 wherein said removing step comprises placing said pieces ofglass in an acid bath for a period of time sufficient for removing saidcoating.
 7. The process recited in claim 6 wherein said bath is acircular vibratory conveyor.
 8. The process recited in claim 6 furthercomprising vibrating said pieces of glass while in said bath.
 9. Theprocess recited in claim 6 wherein said period of time is greater thanabout five minutes.
 10. The process recited in claim 3 wherein saidglass is coated with a red dye comprised of an inorganic pigment in asolvent and said removal step comprises bathing said pieces of glass inhydrofluoric acid for a period of time sufficient to remove a majorportion of said red dye.
 11. The process recited in claim 10 furthercomprising agitating said hydrofluoric acid bath.
 12. The processrecited in claim 11 wherein said agitation is intermittent.
 13. Theprocess recited in claim 11 wherein said agitation is continuous. 14.The process recited in claim 10 wherein said period of time to removesaid dye is greater than about five minutes.
 15. The process recited inclaim 10 wherein said period of time to remove said dye is between aboutfive and twenty minutes.
 16. A process comprising:subjecting a feedstock of waste materials comprised of articles and portions thereof madeof glass and nonglass components, articles and portions thereof made ofglass, glass shards and combinations thereof to vibrations in avibrating apparatus at a frequency, impact force and for a period oftime effective for breaking said glass components into pieces of glassof a first size range and for liberating said glass components from saidnonglass components, portions of said glass in said feed stock beingheld to other portions of said glass by a lead frit; separating anynonglass components present in the feed stock from said pieces of glass;and following said separating step, exposing at least said portions ofsaid pieces of glass held together by said frit to a solution of nitricacid having a concentration of about 12% for a period of time sufficientto remove major amounts of said frit, and agitating said solution duringsaid period of exposure time.
 17. The process recited in claim 16wherein said period of exposure time sufficient to remove said frit isabout ten minutes.
 18. The process recited in claim 16 wherein saidagitation is intermittent.
 19. The process recited in claim 16 whereinsaid agitation is continuous.
 20. The process recited in claim 3 whereinsaid glass is coated with at least one material selected from the groupconsisting of a graphite, a graphite acrylic coating, aluminum,phosphor, iron oxide, sodium silicate, red dye, and combinationsthereof, and said removing step further comprises bathing said pieces ofglass in a solution selected from the group consisting of a hydrofluoricacid solution, ammonium fluoride solution and combinations thereof for aperiod of time sufficient for removing said material.
 21. The processrecited in claim 20 further comprising agitating said solution duringsaid period of time for removing said material.
 22. The process recitedin claim 21 wherein said agitation is intermittent.
 23. The processrecited in claim 21 wherein said agitation is continuous.
 24. Theprocess recited in claim 20 wherein said bathing step occurs in acircular vibratory bed.
 25. The process recited in claim 21 wherein saidsolution is a hydrofluoric acid solution having a hydrofluoric acidconcentration of between about 1-20%.
 26. The process recited in claim25 wherein said hydrofluoric acid concentration is between about 1-5%.27. The process recited in claim 26 wherein said period of time forremoving said material is at least about five minutes.
 28. The processrecited in claim 21 wherein said solution is an ammonium bifluoridesolution having a concentration between about 1.5% to 10% ammoniumbifluoride and said period of time for removing said material is atleast about five minutes.
 29. The process recited in claim 20 whereinsaid period of time for removing said material is between about five toabout ten minutes.
 30. The process recited in claim 20 wherein portionsof said pieces of glass are held to other portions of said pieces ofglass by a lead frit and said bathing step is followed by a secondbathing step comprising bathing at least said portions of said pieces ofglass in a solution of nitric acid having a concentration of about 12%for a period of time sufficient to remove major amounts of said fritwhile agitating said nitric acid solution.
 31. The process recited inclaim 20 further comprising rinsing said pieces of glass following saidbathing step.
 32. The process recited in claim 1 wherein said feed stockincludes glass and nonglass components and said separating stepcomprises:dividing said feed stock exiting said vibrating apparatus intoa first stream of primarily glass pieces and a second stream ofprimarily nonglass components; flowing air over at least said secondstream at a velocity effective for diverting from at least said secondstream lightweight nonglass components; exposing at least said secondstream to a magnetic field of sufficient strength to divert magneticnonglass components from at least said second stream; and removingremaining components of said second stream from the process.
 33. Theprocess recited in claim 32 further comprising passing said stream ofair over said first stream and exposing said first stream to saidmagnetic field to divert from said first stream lightweight and magneticnonglass components.
 34. The process recited in claim 1 wherein saidseparating step compromises removing any nonglass components present insaid feed stock by hand.
 35. The process recited in claim 1 wherein saidfeedstock includes glass and nonglass components and said separatingstep comprises:flowing air over said stream of glass and nonglasscomponents exiting said vibrating apparatus at a velocity effective fordiverting light-weight nonglass components from said stream; exposingsaid stream to a magnetic field of sufficient strength to divertmagnetic nonglass components from said stream; and removing remainingnonglass components from said stream to yield a stream of glasssubstantially free of nonglass components.
 36. The process recited inclaim 1 wherein said glass is comprised of at least first and secondtypes of glass having first and second specific gravities, respectively,and the process further comprises:the step of separating said first typeof glass from said second type of glass by placing said first and secondtypes of glass in a dense suspension medium having a specific gravityless than that of one said type of glass and no less than that of theother said type of glass such that generally all of the one said type ofglass having a specific gravity higher than that of said suspensionmedium will sink forming a sink fraction and generally all of the onesaid type of glass having a specific gravity equal or less than saidsuspension medium will float on said suspension medium forming a floatfraction; and recovering said sink fraction and recovering said floatfraction.
 37. The process recited in claim 36 wherein the specificgravity of said first type of glass is in a range of about 2.8 to 2.9,the specific gravity of said second type of glass is about 2.7 and thespecific gravity of said suspension medium is about 2.7.
 38. The processrecited in claim 36 wherein said suspension medium is selected from thegroup consisting essentially of water suspensions of organic liquids,magnetite, ferro silicons and combinations thereof.
 39. The processrecited in claim 38 wherein said suspension medium is magnetite mixedwith an anionic dispersant.
 40. The process recited in claim 39 whereinsaid anionic dispersant is selected from the group consistingessentially of a ligno-sulfate and an ammonium naphthalene sulfonic acidcondensate polymer.
 41. The process recited in claim 40 wherein saidsuspension medium is a magnetite water slurry having a solids content ofabout 80% solids and the content of said anionic dispersant is about 5%by weight of said solids content.
 42. The process recited in claim 38wherein said organic liquid is tetrabromoethane.
 43. The process recitedin claim 36 further comprising rinsing said sink fraction and said floatfraction following said recovering steps.
 44. A processcomprising:subjecting a feed stock of waste materials comprised ofarticles and portions thereof made of glass and nonglass components,articles and portions thereof made of glass, glass shards andcombinations thereof to vibrations in a vibrating apparatus at afrequency, impact force and for a period of time effective for breakingsaid glass components into pieces of glass of a first size range and forliberating said glass components from said nonglass components;separating any nonglass components present in the feed stock from saidpieces of glass; and following said separating step, crushing saidpieces of waste glass at a rate and for a period of time for effectivefurther breaking said glass into pieces of a second size range smallerthan the pieces of said first size range.
 45. The process recited inclaim 44 further comprising, following the step of crushing said piecesof glass into pieces of a second size range, screening said pieces ofglass to remove therefrom glass fines.
 46. The process recited in claim44 further comprising, following said crushing step, crushing saidpieces of glass a second time to further break said pieces of glass intoa third size range smaller than the pieces of said second size range.47. A process comprising:separating a first type of glass from a mixtureof said first type of glass and at least a second type of glass whereinsaid first type of glass has a specific gravity higher than the specificgravity of said second type of glass, by placing said mixture in a densesuspension medium of magnetite mixed with an anionic dispersant having aspecific gravity less than that of said first type of glass such thatgenerally all of said first type of glass sinks to form a sink fractionand generally all of said second type of glass floats on said suspensionmedium to form a float fraction; and recovering said sink fraction andrecovering said float fraction.
 48. The process recited in claim 47wherein said anionic dispersant is selected from the group consistingessentially of a ligno-sulfate and an ammonium naphthalene sulfonic acidcondensate polymer.
 49. The process recited in claim 53, wherein saidsuspension medium comprises a magnetite water slurry having a solidscontent of about 80% and an anionic dispersant present in an amount ofabout 5% by weight of said solids content.